Certain disease states require treatment using one or more different medicaments. Some drug compounds need to be delivered in a specific relationship with each other in order to deliver the optimum therapeutic dose. Here, combination therapy may be desirable, but not possible in a single formulation for reasons such as, but not limited to, stability, compromised therapeutic performance and toxicology.
For example, in some cases it might be beneficial to treat a person suffering from diabetes with a combination of a long acting insulin along with a glucagon-like peptide-1 (GLP-1). This GLP-1 is derived from the transcription product of the proglucagon gene. GLP-1 is found in the body and is secreted by the intestinal L cell as a gut hormone. GLP-1 possesses several physiological properties that make it (and its analogs) a subject of intensive investigation as a potential treatment of diabetes mellitus.
A number of potential problems can arise when delivering two active medicaments or “agents” simultaneously. As just one example, the two active agents may interact with each other during the long-term, shelf life storage of the formulation. Therefore, there are certain advantages to storing the active components separately and combine them at the point of delivery, e.g. injection, needle-less injection, pumps, or inhalation. However, the process for combining the two agents needs to be simple and convenient for the user to perform reliably, repeatedly and safely.
One further concern is that the quantities and/or proportions of each active agent making up the potential combination dose or therapy may need to be varied for each user or at different stages of their therapy. Again, as just one example, one or more active agents may require a titration period to gradually introduce a patient to a “maintenance” dose. A further example would be if one active agent requires a non-adjustable fixed dose while the other is varied in response to a patient's symptoms or physical condition. This problem means that pre-mixed formulations of multiple active agents may not be suitable as these pre-mixed formulations would have a fixed ratio of the active components, which could not be varied by the healthcare professional or user.
Additional concerns arise where a multi-drug compound therapy is required, because certain users cannot cope with having to use more than one drug delivery system or make the necessary accurate calculation of the required dose combination. This is especially true for users with dexterity or computational difficulties.
Other problems could arise where a user may attempt to re-use a non-sterile needle after a certain dose combination has been delivered. Using such a non-sterile needle may lead to the transmission of certain diseases (septicaemia) and therefore there exists a need for a medicated module that prevents needle re-use. There is a further concern of inadvertent needle sticks with certain needle assemblies where the injection needle is not concealed or covered, especially after use when a needle may be contaminated with blood. As such, there is also a general need to reduce certain patient's needle anxiety that may heighten a patient's fear or phobia of exposed needles.
Accordingly, there exists a strong need to provide devices and methods for the delivery of two or more medicaments in a single injection or delivery step that is simple and safe for the user to perform and that also tends to reduce a patient's anxiety towards injections or needles.